He was known for leading a movement to petition the government of Qing Dynasty China to rescue the Ryūkyū Kingdom from annexation by Imperial Japan.
Having been chosen to start on the track to becoming a bureaucrat, he traveled to China to study at the age of 26, remaining at the Imperial Academy in Beijing for seven years.
Worrying about the future of the Ryūkyū Kingdom, Rin Seikō left for China with Kōchi Chōjō and Sai Taitei (蔡大鼎) for help.
With the Ryūkyū-kan in Fuzhou as their base, Rin and Kōchi petitioned the government of Qing Dynasty China to rescue the Ryūkyū Kingdom from annexation by Imperial Japan, but there was little response.
Rin Seikō went to Beijing to request that China send troops to the Ryūkyū Islands in the next year, but there was little response.